cateidchoices.java

java课程的资料以及实验的代码

import java.sql.*;
import java.math.*;

public class CateIdChoices {
   Connection conn;
   public CateIdChoices() {
   	conn = (new DbConn()).getConnection();
   }
   public int selCateCnt() {
      int cnt=0;
      if (conn == null) {
      	System.out.println("Can not connected yet!");
      	return -1;
      }
      try {
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery ("select count(distinct cateid) from category");
      while (rset.next()) {
        cnt = rset.getInt(1);
      }
      rset.close();
      stmt.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
      return cnt;
   } 
    
   public void selCateId(String [] scnt) {
      int k=0;
      String sql;
      if (conn == null) {
      	System.out.println("Can not connected yet!");
      	return;
      }
      try {
      sql = "select distinct cateid from category";
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery (sql);
      while (rset.next()) {
        scnt[k++] = rset.getString(1);
      }
      rset.close();
      stmt.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
   }
    
    public int selSubCateCnt(String cid) {
      int cnt=0;
      if (conn == null) {
      	System.out.println("Can not connected yet!");
      	return -1;
      }
      try {
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery ("select count(subcateid) from category where cateid = '"+cid+"'");
      while (rset.next()) {
        cnt = rset.getInt(1);
      }
      rset.close();
      stmt.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
      return cnt;
   } 
   
   public void selSubCateId(String [] scnt,String cid) {
      int k=0;
      String sql;
      if (conn == null) {
      	System.out.println("Can not connected yet!");
      	return;
      }
      try {
      sql = "select subcateid from category where cateid = '"+cid+"' order by subcateid";
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery (sql);
      while (rset.next()) {
        scnt[k++] = rset.getString(1);
      }
      rset.close();
      stmt.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
   }
}